<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>CSS背景之背景颜色</title>
</head>

<body>
    background-color: transparent(透明) / color;
    <br>
    默认是transparent
</body>

</html>